Diode Circuit Board - Toro Groundsmaster 4000-D Service Manual

Diode Circuit Board

The circuit board contains four diodes (Fig. 48) and is lo-
cated under the console housing. The diodes are used
for circuit protection from inductive voltage spikes that
occur when a hydraulic valve solenoid is de--energized.
Diode D1 is in the left cutting deck circuit, D2 is in the
Transport/Mow circuit, D3 is in the front cutting deck cir-
cuit and D4 is in the right cutting deck circuit.
Testing
The diodes can be individually tested using a digital
multimeter (ohms setting) and the table to the right. If
any of the diodes are faulty, the diode circuit board must
be replaced.
Apply dielectric grease (Toro part number 107--0342) to
circuit board contacts whenever the circuit board is
installed into the wire harness.
Electrical System
CIRCUIT BOARD
Red Lead (+)
on
Terminal
H
A
G
B
F
C
E
D
Page 5 - - 30
DIODE DIAGRAM
Figure 48
Black Lead (- -)
on Continuity
Terminal
A YES
H
B YES
G
C YES
F
D YES
E
Groundsmaster 4000--D
H
G
F
E
D
C
B
A
NO
NO
NO
NO